DE-A-1814269 discloses a selvedge apparatus of the type cited above characterized by a frame, whereby at least one needle pair is placed in the frame and whereby the needle pair is oriented in parallel to the longitudinal axis of the frame and can also pivot around the longitudinal axis of the frame. The frame itself is fastened to the last heddle shaft. Such a selvedge apparatus is particularly well suited for the fastening of fiberglass threads or yarns to a leno selvedge with a corresponding fabric. The two needles of the needle pair each have an eye on their end through which the leno thread is passed. In the vicinity of the needle pair, the frame has a slot along the frame through which the core thread is guided. The core thread, in combination with the two leno threads guided through the eyes of the needles and the weft threads, ensures the binding of the selvedge, whereby the weft threads run perpendicular to the core thread. For the alternating pivoting of the at least one needle pair around the longitudinal axis of the frame, the disclosed embodiment describes an electromagnetic drive.
The electromagnetic drive comprises an axis mounted in a spool, whereby such a drive has different disadvantages. Such a drive is relatively heavy; this is particularly notable because this drive must be moved using the drive for the heddle shafts. That means that higher weight on the heddle shafts requires a higher drive output for the drive of the loom. Moreover, such a drive is relatively slow, that is, such a drive cannot be used for looms with a high number of picks per minute of 700 or more. Furthermore, an electromagnetic drive is highly inaccurate, so that it cannot be ensured that after each pick the weft thread will be properly tied off. The efficiency is also low.
The task of the invention is thus to provide a drive for a device of the type noted above that is very light in weight in order to keep the drive power of the loom low for the movement of the heddle shafts, that moreover works with high precision, is relatively insensitive to contamination, and has a high efficiency.